1. Field of the Invention
The invention relates generally to communications systems, and, more particularly, to a novel frequency or phase modulator system.
2. Description of Related Art Including Information Disclosed Under .sctn..sctn. 1.97-1.99
U.S. Pat. No. 3,147,437, issued Sept. 1, 1964 to Crafts et al discloses a single side band radio carrier retrieval system in which a base band input signal is modulated by a phase shifter which adds or subtracts phase from an existing phase that increases linearly with time.
U.S. Pat. Nos. 3,546,386, issued Dec. 8, 1970 to Darcey and 3,714,577, issued Jan. 30, 1973 to Hayes disclose modulation systems which utilize conventional frequency modulators.
U.S. Pat. Nos. 4,019,140, issued Apr. 19, 1977 to Swerdlow and 4,310,920, issued Jan. 12, 1982 to Hayes disclose single side band radio systems which utilize conventional phase and amplitude modulators.
U.S. Pat. No. 4,375,082, issued Feb. 22, 1983 to Lohrmann, which is incorporated herein by reference, discloses a high speed rectangular function generator for generating a rectangular output voltage in response to a varying input voltage. A voltage divider produces switching points in conjunction with the input voltage to switch inversion and non-inversion amplifiers, and the amplifier outputs are summed to produce a rectangular output voltage.